There may be several causes, it is considered that the service center is honest, never seen a dishonest official center.
1) Misunderstanding of language between the parties.
2) The quote was chargeable (device out of warranty) and he does not want to pay it to get his phone back
3) The person is not saying everything, I have rarely seen a phone having suffered battery overheating requiring the battery to be changed, even in a less serious case than this G5S+ in the photo, other damaged components are certainly to be found change.
However, a professional must guarantee its repair, if the user does not want to change what may be damaged (charging circuit for example), he will not only change the battery and return the phone to the state UNLESS he there is a significant risk (case of this G5S+ risk of implosion and fire).
If I send this G5S+ to a professional, the estimate will be much more expensive than a recent device, but a professional will never return this phone to me in the same condition even if I pay him the estimate.
Come on, while waiting for the end of this story, I'm going to put this G5 back in a solid iron box while waiting to find a secure trash solution.
